SYNOPSIS

DESCRIPTION

The reformail program reads a message on standard input, reformats it
in some way, and writes the message to standard output:
Splittingmailboxesintoindividualmessages
The -s option splits the mbox-formatted mailbox file on standard input
into individual messages. An external program is executed for each
message. The contents of each individual message will be provided to
the external program on standard input.
If the FILENO environment variable is set to a number, reformail will
consecutively increment FILENO each time the program is executed for
each individual message.
If FILENO is not set, it's initial value will be "000". If FILENO is
set to a non-numeric value, FILENO will remain unchanged.
Detectingduplicatemessages
The -D option implements a simple way to delete duplicate messages in
incoming mail. filename is a file that will be approximately 'len'
bytes long. This file will be used by reformail to save message IDs
seen in recent mail. reformail reads the message on standard input. If
the message has a Message-ID: header that's already in the cache file,
reformail terminates with the exit code set to 0. Otherwise, reformail
terminates with the exit code set to 1.
Extractingheaders
The -x and -X options extract the indicated headers from the message,
and print them to standard output. Multiple -x and -X options can be
specified at the same time, and may be intermixed.
The -x option extracts and prints the contents of the header. The -X
option prints the name of the header as well.
In all other situations, reformail copies the message on its standard
input to its standard output, reformatting the message as follows:

OPTIONS

-a'header: value'
Append a custom header to the message if this header does not
already exist. If the header is either Message-ID: or
Resent-Message-ID: and the value is empty, reformail generates a
(hopefully) unique message ID for you.
-A'header: value'
Append a custom header to the message even if this header already
exists. If the header is either Message-ID: or Resent-Message-ID:
and the value is empty, reformail generates a (hopefully) unique
message ID for you.
-c
Concatenate multi-line headers. Headers split on multiple lines are
combined into a single line.
-dn
If n is 1, each line will be terminated with CRLF. If n is 0
(default), each line will be terminated with LF. reformail reads a
message with either line terminator, and will force the message to
have the specified line termination.
-f0
Remove the "From_" line from the message, if it's there.
-f1
Add the "From_" line to the message, if it's not there. reformail
will attempt to generate the "From_" line from any Errors-To:,
Return-Path:, or From: headers in the message. "root" will be used
if reformail is unable to determine the return address.
-i'header:value'
Appends a custom header to the message. If this header already
exists it is renamed by prepending "Old-" to the name of the
header.
-I'header:value'
Append a custom header to the message. If this header already
exists in the message, the old header is completely removed. If the
value is empty, any existing header is completely removed, and
nothing gets appended.
-R oldheader: newheader:
Rename the indicated header.
-u'header:'
If this header occurs multiple times in the message, remove all
occurrences except the first one.
-U'header:'
If this header occurs multiple times in the message, remove all
occurrences except the last one.

AUTOREPLIES

The autoreply options from earlier versions of mailbot have been moved
into mailbot(1)[1].

BUGS

For the -a, -A, and -I options, a space after the header name and the
colon is considered to be a non-empty field.
Do not provide the same header to more than one family of
header-modifying options, such as -u/-U and -a/-A. Doing so yields
unpredictable results. It's better to run reformail several times (use
a pipe, perhaps).